/*  This file is part of YUView - The YUV player with advanced analytics toolset
*   <https://github.com/IENT/YUView>
*   Copyright (C) 2015  Institut für Nachrichtentechnik, RWTH Aachen University, GERMANY
*
*   This program is free software; you can redistribute it and/or modify
*   it under the terms of the GNU General Public License as published by
*   the Free Software Foundation; either version 3 of the License, or
*   (at your option) any later version.
*
*   In addition, as a special exception, the copyright holders give
*   permission to link the code of portions of this program with the
*   OpenSSL library under certain conditions as described in each
*   individual source file, and distribute linked combinations including
*   the two.
*   
*   You must obey the GNU General Public License in all respects for all
*   of the code used other than OpenSSL. If you modify file(s) with this
*   exception, you may extend this exception to your version of the
*   file(s), but you are not obligated to do so. If you do not wish to do
*   so, delete this exception statement from your version. If you delete
*   this exception statement from all source files in the program, then
*   also delete it here.
*
*   This program is distributed in the hope that it will be useful,
*   but WITHOUT ANY WARRANTY; without even the implied warranty of
*   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
*   GNU General Public License for more details.
*
*   You should have received a copy of the GNU General Public License
*   along with this program. If not, see <http://www.gnu.org/licenses/>.
*/

#ifndef FRAMEHANDLER_H
#define FRAMEHANDLER_H

#include <QImage>
#include <QObject>
#include <QSettings>

#include "common/saveUi.h"
#include "common/typedef.h"

#include "ui_frameHandler.h"

struct infoItem;

/* The frame handler is the base class that is able to handle single frames. The class videoHandler is a child
 * of this class and adds support for sources with more than one frame. Finally, there are even more specialized
 * video classes that inherit from the videoHandler. 
 * This class handles the basics of an image and the corresponding controls (frame size). It handles drawing of the
 * frame (drawFrame).
*/
class frameHandler : public QObject
{
  Q_OBJECT

public:

  // Create a new blank frameHandler. Don't forget to load an image from file (loadCurrentImageFromFile).
  frameHandler();
  
  // Get the size/bit depth of the (current) frame
  QSize getFrameSize() const { return frameSize; }
  int getImageBitDepth() const { return currentImage.depth(); }
  
  // Draw the (current) frame with the given zoom factor
  void drawFrame(QPainter *painter, double zoomFactor, bool drawRawValues);

  // Set the values and update the controls. Only emit an event if emitSignal is set.
  virtual void setFrameSize(const QSize &size);

  // Return the RGB values of the given pixel. If a second item is provided, return the difference values to that item.
  virtual QStringPairList getPixelValues(const QPoint &pixelPos, int frameIdx, frameHandler *item2=nullptr, const int frameIdx1=0);
  // Is the pixel under the cursor brighter or darker than the middle brightness level?
  virtual bool isPixelDark(const QPoint &pixelPos);

  // Is the current format of the frameHandler valid? The default implementation will check if the frameSize is
  // valid but more specialized implementations may also check other things: For example the videoHandlerYUV also
  // checks if a valid YUV format is set.
  virtual bool isFormatValid() const { return frameSize.width() > 0 && frameSize.height() > 0; }

  // Calculate the difference of this frameHandler to another frameHandler. This
  // function can be overloaded by more specialized video items. For example the videoHandlerYUV
  // overloads this and calculates the difference directly on the YUV values (if possible).
  virtual QImage calculateDifference(frameHandler *item2, const int frameIdxItem0, const int frameIdxItem1, QList<infoItem> &differenceInfoList, const int amplificationFactor, const bool markDifference);
  
  // Create the frame controls and return a pointer to the layout. This can be used by
  // inherited classes to create a properties widget.
  // isSizeFixed: For example a YUV file does not have a fixed size (the user can change this),
  // other sources might provide a fixed size which the user cannot change (HEVC file, PNG image sequences ...)
  // If the size is fixed, do not add the controls for the size.
  virtual QLayout *createFrameHandlerControls(bool isSizeFixed=false);

  // Draw the pixel values of the visible pixels in the center of each pixel.
  // Only draw values for the given range of pixels and frame index.
  // The playlistItemVideo implementation of this function will draw the RGB vales. However, if a derived class knows other
  // source values to show it can overload this function (like the playlistItemYUVSource).
  // If a second frameHandler item is provided, the difference values will be drawn. For the second item, a second
  // frame index must be provided (set markDifference if you want only differing values to be marked).
  virtual void drawPixelValues(QPainter *painter, const int frameIdx, const QRect &videoRect, const double zoomFactor, frameHandler *item2=nullptr, const bool markDifference = false, const int frameIdxItem1=0);
  
  QImage getCurrentFrameAsImage() const { return currentImage; }

  // Load the current image from file and set the correct size.
  bool loadCurrentImageFromFile(const QString &filePath);
 
signals:
  // Signaled if something about the item changed. redrawNeeded is true if the handler needs to be redrawn.
  void signalHandlerChanged(bool redrawNeeded, recacheIndicator recache);

protected:

  QImage currentImage;
  QSize  frameSize;

  // Get the pixel value from currentImage. Make sure that currentImage is the correct image.
  QRgb getPixelVal(const QPoint &pos)    { return getPixelVal(pos.x(), pos.y()); }
  virtual QRgb getPixelVal(int x, int y) { return currentImage.pixel(x, y); }

  // When slotVideoControlChanged is called, update the controls and return the new selected size
  QSize getNewSizeFromControls();

  QSettings settings;

private:

  // A list of all frame size presets. Only used privately in this class. Defined in the .cpp file.
  class frameSizePresetList;

  // The (static) list of frame size presets (like CIF, QCIF, 4k ...)
  static frameSizePresetList presetFrameSizes;
 
  SafeUi<Ui::frameHandler> ui;

protected slots:

  // All the valueChanged() signals from the controls are connected here.
  virtual void slotVideoControlChanged();
};

#endif // FRAMEHANDLER_H
